Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
pignĕrātĭo, ōnis, f. [pignero], a pledging, pawning, mortgaging (jurid. Lat.): pignerationem recipere, Dig. 20, 1, 9; Cod. Just. 8, 34, 3, § 3.